如何混合映射的“参考”并列出“无参考”；一个域类中有许多关系？

发布于 2024-11-05 08:32:01 字数 504 浏览 5 评论 0原文

在 Grails 中，hasMany 允许一个域类与另一个域类建立级联has Many关系。使用 hasMany 时有两种主要的关系样式：映射属性引用和列出无属性引用。

带有属性引用的 hasMany：

class Car {
     static hasMany = [parts:Part, wheels:Wheel]
}

没有属性引用的 hasMany 关系：

class Car {
     static hasMany = [Part, Wheel]
}

问题来了，如何混合上述两种样式？

假设我想要直接引用轮子，但我不想要零件的域属性引用。

我该如何在域类中编写此代码？

原文

In Grails hasMany allows one domain class to establish a cascading has many relationship with another domain class. There are two main styles of relationships when using hasMany: a mapped property Reference and listed no property reference.

hasMany with property references:

class Car {
     static hasMany = [parts:Part, wheels:Wheel]
}

hasMany relationships without property references:

class Car {
     static hasMany = [Part, Wheel]
}

Here's the problem, how do I mix the two above styles?

Say I want to have a direct reference to the Wheels, but I don't want a domain property reference for the Parts.

How would I write the code for this in the Domain Class?

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记忆消瘦 2024-11-12 08:32:01

class Car {
     Set wheels // could also use List, if you wanted indexed property
     static hasMany = [Part, Wheel]
}

但问题是，即使您没有定义它，您最终也会在您的域中得到一个Setwheels。如果您查看最新的 Grails 网站上的文档，地图版本是更常见的方法。

class Car {
     Set wheels // could also use List, if you wanted indexed property
     static hasMany = [Part, Wheel]
}

Here's the rub though, even if you don't define it, you will end up with a Set wheels in your domain. And if you look at the latest documentation on the Grails web site, the map version is the more common approach.

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